I have rust on the same spot as you do and I think is it normal. I had my truck for 6 years, since new and I haven't had any water problem. I will try to use a wire brush, clean up the area and apply some paint to it. That is the only place that I can see any rush.

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2010 X6 50i
2005 X5 3.Oi, Many Options
2015 HONDA CR-V EX-L
1998 ACURA 2.5TL

MODs
- Driver's outside mirror light
- Voice Recognition Module
- Blaupunkt Entertainment System
with Digital TV